Soils of Bruce County, South Island, New Zealand
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UBRARV LANDCARE RESEARCH N7 P.O. BOX 69, LINCOLN, NZ New Zealand Soil Bureau Soils of Bruce County, South Island, New Zealand N.M. KENNEDY N.Z. Soil Survey Report 87 Landcare Research NZ 11 11 11 111 111 11 111 1111111 111 1111111111 1111 111111 11111111 L0010 4 414 NZ soi I su .. vey report '5 7 SOILS OF BRUCE COUNTY., SOUTH ISLAND, NEW ZEALAND N.M. Kennedy Soil Bureau, Lower Hutt N.Z. Soil Survey Report 87 New Zealand Soil Bureau Department of Scientific and Industrial Research Lower Hutt, New Zealand 1983 Editor: H. Simmonds Typing: Tessa Roach Draughting: M. Smith KENNEDY, N.M. 1983: Soils of Bruce County, South Island, New Zealand N.Z. Soil Survey Report 87 50p. Includes: Kennedy, N.M. 1981: Soil map of Bruce County, South Island, New Zealand. 1:100 OOO N.Z. Soil Bureau Map 159 ISSN 0110-2079 P. D. HASSELBERG, GOVERNMENT PRINTER, WELLINGTON, NEW ZEALAND-1983 CONTENTS page SUMMARY .................................................................................. ;....................................................................... 5 INTRODUCTION TO SOIL-FORMING FACTORS ..................................................................................... 5 THE SOIL MAP ............................................................. .-..................................................................................... 5 Soil taxonomic and soil mapping units .............................................................................................................. 5 SOIL GROUPS OF BRUCE COUNTY ............................................................................................................ 7 Yellow-grey earths ................................................................................................................................................ 7 Intergrades between yellow-grey earths and yellow-brown earths .................................................................... 8 Yellow-brown earths ............................................................................................................................................ 8 Podzolised yellow-brown earths .......................................................................................................................... 8 Intergrades between rendzinas and yellow-grey earths ...................................................................................... 9 Brown granular loams and clays ......................................................................................................................... 9 Yell ow-brown sands ............................................................................................................................................. 9 Organic soils .......................................................................................................................................................... 9 Gley soils ............................................................................................................................................................... 9 Recent soils ......................................................................................................................................................... 10 Saline gley recent soils ....................................................................................................................................... 10 CLASSIFICATION OF SOILS ACCORDING TO THEIR LIMITATIONS FOR LAND USE ............... 10 Pastoral use ......................................................................................................................................................... 10 Cropping .............................................................................................................................................................. 11 Forestry ................................................................................................................................................................ 12 Potential land use ............................................................................................................................................... 12 Value for food production ................................................................................................................................. 13 ACKNOWLEDGMENTS .................................................................................................................................. 14 REFERENCES .................................................................................................................................................... 14 APPENDIX-EXTENDED LEGEND ............................................................................................................. 15 Explanatory notes ............................................................................................................................................... 15 INDEX TO SOIL SERIES IN EXTENDED LEGEND ................................................................................. 50 Figures l Location maps ................................................................................................................................................. 4 Tables 1 Legend of soils arranged pedologically ......................................................................................................... 6 2 Soil limitations for pastoral use .................................................................................................................. 10 3 Soil limitations for cropping ........................................................................................................................ 11 4 Soil limitations for forest growth ................................................................................................................ 12 5 Classes indicating potential use of soils ...................................................................................................... 12 6 Value of soils for food production .............................................................................................................. 13 4 PACIFIC OCEAN 10km 0 -- 1. 500000 Scale · dary ••••••• survey boun NEW ZEALAND South Island TASMAN SEA PACIFIC OCEAN Figure I Location maps 5 SUMMARY This report briefly introduces the soils of Bruce County which has been mapped at a scale of 1: 100 OOO and covers approximately 132 300 ha. The soil map is a compilation prepared from published and unpublished soil surveys carried out by officers of N.Z. Soil Bureau over a number of years. The soils are classified according to the N.Z. genetic soil classification. Salient physical and chemical properties of each soil group are summarised in the text while important properties of individual soils are tabulated in the extended legend (Appendix). Finally, the individual soils are rated according to their limitations for pastoral, cropping and forestry uses, and also to their potential use and value for food production. INTRODUCTION TO SOIL-FORMING FACTORS Bruce County covers approximately 132 300 ha level; the land east of the Titri fault rises sharply and is one of the smaller counties in Otago. It is to 430 m above sea level while that to the west of bounded on the south by the Clutha River, on the the depression rises gradually to 675 m. To the east by the Pacific Ocean, on the north by the Taieri south, the depression falls away to l 0 m above sea and Waipori Rivers and on the west by an arbitrary level where it joins the extensive flood plains asso but irregular line between Waitahuna Hill, Mt ciated with the Clutha River. Stuart and Tuapeka Mouth on the Clutha River. Rainfall ranges from 750 to 1100 mm per year The principal town is Milton, 55 km south of on the uplands, decreasing to 625 mm per year on Dunedin, with a population of 2180 ( 1973). The the lowlands adjacent to the Clutha River. The larger town of Balclutha on the south-east bound mean average temperature of the area is 10°C, and ary is not included in the county (Fig. I). wind is predominantly from the south-west. The uplands climate is cool with snow and mist in The area is bisected by the Tokomairiro depres winter. sion which contains Late Pleistocene sediments, bounded in the east by greywacke, schist, Upper The soil-forming vegetation was principally tus Cretaceous and Tertiary rocks, and in the west by sock grasses with dicotylous (broadleaf) - podocar·p schist and greywacke capped by remnants of forest along the coastal hills. younger sediments and volcanic rocks. The eastern The principal parent material of the soils formed edge of the depression is the Titri fault, along which in Bruce County is schist loess, which usually forms rocks have been uplifted and tilted to the east. a distinct mantle over the schist, greywacke, Upper Similar uplifting and tilting has occurred along the Cretaceous, Tertiary and basaltic rocks. In other Aka tore fault nearer the coast. The elevation of the areas it is incorporated in slope detritus comprised depression varies between I 0 and 60 m above sea mainly of rock fragments. THE SOIL MAP The soil map accompanying this report is a com In many parts of the county, new surveys were pilation prepared from published and unpublished carried out, either to complete the area or to update soil surveys carried out by officers of N.Z. Soil earlier information. Bureau over a number of years. 'General survey of the soils of South Island, New Zealand ' (N .Z. Soil Bureau l 968a) provided the SOIL TAXONOMIC AND SOIL MAPPING basis of the